Highly conductive ordered ion exchange membranes

ABSTRACT

Process for producing ion exchange membranes. A matrix material that comprises a polymeric component chosen from the group consisting of monomeric and oligomeric polymer precursors and cross-linkable polymers is provided. Ion cation or anion exchange particles, or proton or hydroxyl or ion conducting particles, or cation or anion exchange polymers, or proton or hydroxyl or ion conducting polymers are introduced in the matrix. The particles are mixed or the polymer is dissolved with the matrix. The resulting mixture is formed into membrane configuration. The particles or the domains of the polymer formed by polymer-matrix phase separation upon solvent evaporation or cooling, are ordered by an electric field. If the matrix comprises or consists of a polymer precursor or a cross-linkable polymer, the precursor is cured concurrently with the ordering of the particles, or if the matrix comprises a polymer solution or polymer melt the polymer solution is evaporated or the polymer melt is maintained and then cooled concurrently with the ordering of the particles.

FIELD OF THE INVENTION

This invention relates to ion conducting membranes in general, orspecifically without limitation ion exchange and/or proton or hydroxylconducting membranes for use in electrodialysis as ion selectivemembranes and in power sources such as fuel cells as proton or hydroxylion conductive separators. Specifically, this invention relates to a newmethod for preparing heterogeneous membranes that have a bettercombination of improved stability, conductivity and/or selectivity thanthe prior art ones.

BACKGROUND OF THE INVENTION

Ion exchange membranes (IEM) are used in electrodialysis (ED) as ionselective membranes and in power sources such as fuel cells as protonconductive separators. Basically, two types of IEMs for use in ED areavailable: homogeneous, that is composed of a cross-linked polymer,which is chemically treated to bind ion exchange groups onto itsskeleton. The other type, heterogeneous IEM, are prepared by randomfilling of a neutral polymer matrix such as polyethylene by tens ofmicron sized ion exchange particles, and often they are reinforced witha net made of polymeric material such as polyamide or PES.

Whenever the so-called percolation concentration of the ion exchangepowder is surpassed, an ion conductive permselective, heterogeneousmembrane results.

The normal ion exchange particle concentration in the matrix required toattain reasonable ion transport through the membrane is 50 to 70% byweight. At these concentrations, the membrane specific electricalconductivity is in the range 4 to 12 mScm⁻¹. In fact, the aboveconcentrations are the maximum possible for the ED application: anattempt to increase ion exchanger concentration beyond this range forobtaining higher conductivity results in loss of membrane strength andreduced shape stability due to increased swelling when exposed to saltsolutions. These properties are important when membranes are used in EDstacks since they limit conditions under which these membranes can beoperated.

In power sources, such as batteries and fuel cells selective ionconducting membranes are used. For example particularly with fuel cells,the Nafion membrane (homogeneous cation exchanger) is widely usedbecause of its remarkable proton conductance (0.15 mScm⁻¹) and stabilityin oxidizing conditions. However, the new fuel cell generations requireboth high proton conductivity and very low permeability to the fuel (forexample, hydrogen or methanol fuels). Inorganic or hybridinorganic-organic composite membranes (both of the heterogeneous type)are today under intensive development for these purposes. One problemencountered in this development is that, as proton conductivity oranionic conductivity in general increase, selectivity to the fueldecreases.

U.S. Pat. No. 3,180,814 discloses a method of increasing conductivity inion exchange membranes made of synthetic resin through the membranewhile the synthetic resin is above its yield point in relation to themagnitude of the electric current. In heat softenable material this maybe accomplished by heat development incidental to the passage of theelectric current, or by heating of the liquid within which the membranematerial is immersed, or by a combination of both. In a material that isnot heat-softenable, this may be accomplished by temporary softening,for example by addition of a solvent.

U.S. Pat. No. 5,232,719 describes a process for producing aprotein-oriented membrane which is enhanced physically and chemically byorienting protein and cross-linking the oriented protein together.

U.S. Pat. No. 6,287,645 describes a method of forming an oriented film.A target is provided and material from the target is ablated onto asubstrate to form a film.

U.S. Pat. No. 5,167,551 describes a process for the production of aheterogeneous ion-exchange membrane, which comprises making a finelypowdered ion exchange material with a crystalline polyolefin resin,forming the resultant mixture into a membrane-shaped article andtreating this latter with an aqueous solution of an alkali metal orammonium salt.

U.S. Pat. No. 5,346,924 discloses a method for making a heterogeneousion exchange membrane, which comprises polyethylene as a binder,incorporates ion exchange resin materials. Said membrane beingfabricated using extrusion or other melt processing procedures.

It is a purpose of this invention to produce heterogeneous ion exchangemembranes (IEM) for ED or fuel cells wherein the particle or domainthreshold concentration needed for conductivity is considerably reduced.

It is another purpose of this invention to provide a method forpreparing heterogeneous membranes that are more stable and moreconductive than the ones known in the art for the application inelectrodialysis (ED) and in power sources such as fuel cells.

It is a further object of this invention to produce such membraneshaving higher permselectivity, higher conductivity, lower swelling rateand better mechanical stability and processability.

It is a still further purpose of this invention to produce membraneswith high proton conductivity and low permeability to fuels such asmethanol or hydrogen gas.

It is a still further purpose of this invention to produce suchmembranes at a reduced production cost.

It is a still further purpose of this invention to produce suchmembranes having increased ion conductance, in particular protonconductance and permeation rate.

Other purposes and advantages of the invention will appear as thedescription proceeds.

SUMMARY OF THE INVENTION

One process for producing ion exchange membranes according to theinvention comprises the following steps: providing a matrix material,which may comprise or consist of a polymer or a polymer precursor;Introducing in said matrix ion cation or anion exchange particles, orproton or hydroxyl or ion conducting particles or any combination of ionexchange, proton, hydroxide and ion conductivity, or cation or anionexchange polymers, or proton or hydroxyl or ion conducting polymers orany combination of ion exchange, proton, hydroxide and ion conductivity;mixing said particles with said matrix; forming said mixture into amembrane configuration; Ordering by an electric field said particles orordering by an electric field the domains of said polymer formed bypolymer-matrix phase separation upon solvent evaporation or cooling; ifsaid matrix comprises or consists of a polymer precursor or across-linkable polymer, said precursor is cured concurrently with saidordering of said particles, or if the matrix comprises a polymersolution or polymer melt the said polymer solution is evaporated or thesaid polymer melt is maintained and then cooled concurrently with saidordering of said particles.

In another process for producing the ordered membranes of this inventionthe electric field orders a phase or domain of ion or proton conductingor exchange polymers or oligomers, [or a precursor of such a polymers oroligomers], which form due to the incompatibility [phase separation]between the said polymers or oligomers and the material of the matrix.The final membrane that forms upon solvent removal from a wet film orcooling of polymer melt mixtures which causes ionic polymer/oligomersphase separation from the matrix material (which may be polymers thatare organic, inorganic or a mixture of both organic or inorganic)resulting in domains or volumes of conducting or ion exchange materialsin a matrix. The application of an electric field across the wet ormolten film as the aforementioned phases or domains are forming willorder the more polar or ionic charged conducting component. Thisordering by the electric field significantly increases the flux andconductivity of the final membrane as compared to a membrane, which areformed without the application of the electric field. This ordering mayalso significantly increase the selectivity of the membrane becausesmaller quantities of conductive materials may be used in a nonconducting matrix, to achieve the same conductivity as a membrane with ahigher content of conducting materials but which has not undergone theinvented ordering. The domain size may be on the scale of 1 nano-meterto tens or hundreds of microns.

Since the membrane is formed by a matrix material which is often fluidor flowable or is a solute in a solvent in its initial states, formingsaid mixture into a membrane configuration includes bringing it to asolid state. If said material is fluid or flowable because it contains asolvent, it is brought to a solid state by evaporating the solvent. Ifit is in a molten state, it is solidified by cooling. If it is fluid orflowable because it consists of or comprises a polymer precursor that ismonomeric or oligomeric or a polymer that should be and is notcross-linked, said precursor is cured. By “curing” is meant hereinpolymerizing and/or cross-linking to form the desired, final polymericstructure. In preferred embodiments, when the mixture is formed into amembrane configuration the electric field should be applied while thesolvent is being evaporated or while the molten polymer is being cooledor while a polymer precursor is being cooled. If a solid membrane isplaced within the electrode system it may be heated above its Tg or Tmpoint to facilitate the particle orientation and then cooled.

The membrane configuration may be a flat sheet, a tubular capillary orhollow fiber, the flat sheet configuration being preferred in manyapplications.

The said ordering, and possibly polymerizing and curing, operation mayproduce concurrent effects, such as solidifying the matrix, evaporatingany solvent and the like.

In one preferred embodiment, the polymeric matrix is chosen from thegroup consisting of polyethylene, polypropylene, polyamides,polybenzimidazole, polysulfones, polyether sulfones, polyether ketones,polyether ether ketones, polyvinylidene fluoride, polyvinylidenecopolymers, polyvinylidene fluoride copolymers, polyvinylidene chloridecopolymers, polyvinyl copolymers, and other engineering plastics, andany other material that is homogeneously mixed with ion exchangematerial, even at elevated temperatures not exceeding 450° C.,preferably not exceeding 250° C., and most preferably not exceeding 150°C., and that is chemically resistant to some extent in acids and basesand to oxidizing environment.

The conductive or/and ion exchange particles may be inorganic or organicor hydrides of inorganic and organic particles. The inorganic conductiveor ion exchange particles may be chosen without limitation for silica orsilicone dioxide, titanium dioxide or zirconium dioxide and zirconiumphosphate. The inorganic materials may also be chosen from non-layeredand layered silicates, such as montmorillonite. The organic or inorganicion exchange particles used according to the invention can be of anycommercially available type. Typical organic ion exchange capacity is 2to 5 meq/g (dry basis) for the cation exchangers and 1 to 3 meq/g (drybasis) for the anion exchangers. The ion exchange particles generallyavailable are mostly from 0.1 to 0.5 mm in diameter, but there are ionexchange particles available as particles of smaller sizes or in theform of powders. The diameter of the particles used, according to apreferred embodiment of the invention, is from 200 to 20 μm, butpreferably 50 to 20 μm. However, nano size particles can also be used inother embodiments. In some cases, it is preferred that the particles bespherically shaped beads. Non-spherical particles may also be preferablyused in other cases. The ion exchange particles are typically organicmaterials, but inorganic or hybrid organic-inorganic ion exchangeparticles may also be used.

The particles are introduced into the polymeric matrix precursor in sucha way as to create a mixture as homogeneous as possible. The mixing maybe facilitated by dissolving the matrix, if polymeric, in a suitablesolvent, or melting it, or treating it with a plasticizer or swellingagent. If a solvent is used, it will be later evaporated, and if thematrix is molten, it will be allowed to solidify. The mixing can beachieved by using a mixing apparatus known in the art, such as mills,mixers, hot presses and the like, depending on the viscosity of thepolymer. The concentration of the ion exchange particles in the mixtureand in the membrane, viz. the ratio of their amount to the overallamount of the matrix and the particles, is from 10 to 70 wt % andpreferably from 20 to 40 wt %.

Additional preferred embodiments are—1) The application of an electricfield across a wet film or gel containing a mixture of at least twocomponents in a common solvent, and 2) a melt where at least onecomponent is dissolved in the melt of at least one of the othercomponents. Upon removing the solvent or reducing the temperature whilethe field is applied results in a solid membrane, wherein the componentsof the fluid or hot melt film have separate into at least two differentphases because of their respective incompatibilities. One phase isdispersed in the other phase which is the matrix, and at least one ofthe dispersed phases (if there is two or more such phase types) isoriented in the electric field. The phase that is ordered is preferablythe polymer or oligomers contains fixed ionic groups sufficient to orderit in the electric fielded. The conditions of application of theelectric field are determined by the temperature during the evaporationof the solvent, the concentration of the solution of the components asit is related to viscosity, the ionic charge of the polymer that isbeing oriented and the dielectric constant of the solvent, matrix andother additives.

The electric field range applied to particles is preferably in the rangefrom 50 to 20,000 V/cm and more preferably from 400 to 1500 V/cm. Theelectric field is a direct or preferably an alternating current fieldand has a frequency preferably from 5 to 2000 Hz and more preferablyfrom 20 to 150 Hz. The time during which the electric field is appliedvaries depending on the viscosity of the matrix precursor, its curingtime and the size and shape of the particles. It may be applied forperiods up to several days but, preferably from several minutes 1 to 10hours. The field may be applied under vacuum, in inert gases, such asargon, nitrogen and the like, or in air over a range of differentrelative humidities. The conductivity of the matrix is detrimental tothe process and should be minimized.

The invention also produces membranes having new properties, that are,in themselves, an aspect of the invention. It is surprising that themethod of this invention produces increased conductivity while retaininghigh selectivity. By “high selectivity” is meant the selective passageof one species, such as protons for example, with the retention of lowpassage of other species, such as H2 or methanol for example.

Conductivity as a function of cation exchange resin content is shown inFIG. 2 together with conductivity obtained with the same compositionsbut without applying electric field during membrane formation. Also, forcomparison, some conductivity values for commercial heterogeneousmembranes are shown in Table I.

TABLE I Cation/anion Membrane type mS/cm exchanger Producer CMH 4 CationMega AMH 8 Anion Mega CPE 12 Cation US-filter MK-40 7 Cation Russian CMT8 Cation Asahi Glass co. Relex CM (CHZ) 6.7 Cation Mega Relex AM (CHZ)7.14 Anion Mega Relex CHM (CHZ) 4.5 Cation Mega Relex AHM 4.5 Anion Mega(CHZ)

Permselectivity shows to what extent the membrane is selective to thecounter ions. This was measured by the traditional method, namely,measuring membrane potential and comparing it to the calculated one (F.Helffrich, 1962, Ion Exchange, New York, McGraw to Hill Publishing Co.).

The results for membranes with different resin concentrations aresummarized in Table II below. The membrane matrix of the membranes ofTable II was silicon rubber (RTV). The ion exchange particles werehome-made spherical cation exchange particles.

TABLE II Measured Measured Ideal Membrane Permselectivity MembranePermselectivity % Resin Measuring Membrane Potential (%) Potential (%)in Solutions, Potential (mV) Ordered (mV) Random Membrane N KCl (mV)Ordered Membrane “Random” Membrane 30 0.5/0.25 15.6 15.6 100 — — 40 15.197 — — 50 15.4 99 15.4 99 60 15.0 96 15.1 97 30 0.1/0.05 16.5 16.5 100 —— 40 16.0 97 — — 50 16.2 98 16.1 97 60 15.5 94 16.2 98 30 0.01/0.00516.7 16.7 100 — — 40 16.9 to — — 50 16.9 — 16.9 100  60 15.9 95 15.9 95

The membrane potential of random membranes (by “random membrane is meantherein a membrane produced without orienting the particles with anelectric field) having less than 50% resin could not be measured, due toinsufficient conductivity.

Swelling extent, indicating the water content within the membrane, isone of the factors governing the conductivity. It was determined fromthe differences in weights between the fully wet and the dried membranewith K+ as the counter ion. Results are presented in Table III below forthe ordered and random (not ordered) membranes. It should be noted thatin all cases the water content is smaller in the ordered membranes ascompared to the random membranes. The membrane matrices of the membranesof Table III were the same as in Table II. The ion exchange particleswere the same as in Table II.

TABLE III Water Water Weight of dry Weight of wet content, content, %Resin In Membrane Membrane % of dry % of dry IE Membrane (g) after 6days (g) Membrane resin 30: random 0.3573 0.4422 23.8 79.2 oriented0.3903 0.4743 21.5 71.7 40: random 0.3640 0.4843 33.0 82.6 oriented0.3537 0.4569 24.2 72.9 50: random 0.3814 0.5438 42.6 85.2 oriented0.3802 0.5276 38.8 77.5 60: random 0.4080 0.6089 49.2 82.1 oriented0.3839 0.5765 48.1 80.2

The thickness of the membranes is preferably 0.2 to 2 mm and morepreferably, 0.2 to 0.5 mm.

For the laboratory production of ordered membranes according to thisinvention, a cell is used which generally consists of two plates of aplastic, e.g. polypropylene, each containing a metal electrode, such asa stainless steel electrode. The two electrodes are separated by anothernon to conductive sheet, e.g. of Teflon, having a hole therein. Thethickness of the sheet and the plan shape and size of its hole depend onthe dimensions of the desired membrane. For instance, the sheet may havea thickness from 0.2 to 2 mm and have a round hole of a few millimetersin diameter, e.g. 10 mm. Said sheet separates the two electrodes andcontains in its hole the membrane mixture.

If the membrane mixture contains a molten or dissolved polymer or othermolten or dissolved substance, the cell should be placed in an ovenwhile applying the electric field and then cooled with the electricfield still on.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 illustrates in exploded perspective view a cell for theproduction of membranes according to the invention;

FIGS. 2 a and 2 b comparatively illustrate the conductivity as afunction of the content of ion exchange resin or particles for amembrane according to an embodiment of the invention and a membrane madewithout the application of an electric field, FIG. 2 a relating tospherical resin particles and FIG. 2 b to resin powder;

FIG. 3 illustrates the variation of the specific conductivity of anordered membrane, containing 20% of ion exchange resin, as a function ofthe strength of the field applied to the membrane;

FIG. 4 illustrates the variation of the specific conductivity of anordered membrane, containing 20% of ion exchange resin, as a function ofthe exposure time to the electric field;

FIG. 5 is a microphotograph of a membrane in the manufacture of which noelectrical field has been applied, so that the particles are disordered;and

FIG. 6 is a microphotograph of a membrane made according to the processof the invention, whereby the particles are seen to have been ordered.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows in exploded view a laboratory cell for producing membranesaccording to an embodiment of the invention. It consists of two plates10 and 11, made of a suitable non-conductive plastic matter, such aspolyethylene. 10 is the upper compartment and 11 is the lowercompartment. Compartment 10 houses an electrode 12 and compartment 11houses an electrode 13. The Teflon sheet has a round hole 15 in thecenter. The hole is round because the membrane to be produced isintended to be round. If a different to shaped membrane is desired, thehole 15 would have a corresponding different shape. The hole 15 isfilled with the mixture of matrix precursor and ion exchange resin, thematrix precursor being fluid or plastic because it has not yet beencured, or is dissolved or molten. Numerals 16 and 17 indicate the twoelectrical contacts through which the alternating electrical field isapplied, from a source not illustrated.

The material, which will form the membrane matrix within which the ionexchange particles are embedded, should have certain properties,preferably: the matrix material and the ion exchange particles shouldform a uniform mixture, the fabrication into a membrane structure shouldbe easily carried out, the material should be stable during membraneformation, particle orientation, and in use. In particular, the startingmatrix material or its precursors may be-a solid in the form ofirregular shaped particle, fibers or regular shaped particles such asspheres; a gel; or a low viscosity liquid, an intermediate or highviscosity liquid, or a thermo-elastic material.

In the last case, the liquid precursors to the matrix may be mixturescomprising a solvent into which liquid monomers, oligomers and/orpolymers are dissolved or/and dispersed if one or more of the componentsare not soluble. The solvent itself may be one or more liquid monomers,oligomers or liquid polymers or a common low molecular weight solvent.These components may be in the liquid state slightly below roomtemperature, room temperature or at elevated temperatures of up to 200°C. but preferably below 120° C.

One important embodiment of this invention are membranes with highselectivity, wherein said property allows a high permeability for onecomponent in a mixture while a second component has a low or very lowpermeability. This permits the separation of each component intodifferent compartments.

In one preferred application of this invention protons are passed from afirst electrode compartment to a second electrode compartment, while thesource of the protons, such as methanol or hydrogen gas, is retained inthe first electrode compartment. Thus a selectivity greater than in theprior art is achieved by using a relatively low concentration of ionexchange particles in the membrane, but ordering them for highconductivity of the protons. The matrix is chosen to be impermeable tothe component to be obtained.

Material candidates may differ in different embodiments of theinvention.

1) In a first embodiment the conductive or ion exchange particles may bedispersed in a polymer melt or liquid at elevated temperature formedinto a membrane, oriented in an electric field and then cooled to asolid under an electric field to form the conductive membrane.

In one approach of this embodiment, a membrane may be formed by mixinguniformly a powder of the matrix with the powder of ion exchangeparticles, placing this mixture into a mold, the bottom of which is anelectrode, covering the mold with another electrode and heating abovethe melting point of the polymer. The molten polymer will flow aroundthe solid exchange particles, and the ion exchange particles will orientthemselves in the electric field. The heat is then removed and thepolymer solidifies to give the desired membrane.

In another variant of this embodiment, a preexisting heterogeneousmembrane is placed between two electrodes, heated above the Tg or Tm ofthe matrix material, the electric field is applied, then the membrane iscooled to give the oriented membrane. The particle or domainheterogeneity may be in the range of 1 nano-meter to tens or hundreds ofmicrons.

2) In a second embodiment the ion exchange or conductive particles maybe dispersed in a viscose liquid of monomers, oligomers or/and polymers,at room or elevated temperature, be formed into a membraneconfiguration, the ion exchange particles be oriented in an electricfield wherein the components of the solution undergo reaction during thetime the electric field is applied, to form a solid matrix with theoriented particles fixed within the matrix.

3) In a third embodiment, the ion exchange or conductive particles maybe dispersed in a viscose liquid comprising a polymer dissolved in asolvent, be formed into a membrane configuration, be oriented in anelectric field wherein the solvent is evaporated during the time theelectric field is applied, to form a solid matrix with the orientedparticles fixed within the matrix.

4) In the fourth embodiment, the application of an electric field acrossa fluid film or a hot melt or gel containing a mixture of at least twocomponents in a common solvent, or a melt where one components isdissolved in the melt of the other component. Upon removing the solventor reducing the temperature while the field is applied results in asolid membrane, wherein the components of the wet or hot melt film haveseparate into at least two different phases because of their respectiveincompatibilities, brought about by evaporating the solvent or cooling.One phase is dispersed in the other phase which is the matrix, and atleast one of the dispersed phases is oriented in the electric field. Thephase that is ordered is preferably the polymer or oligomerscharacterized by conductivity ion exchange or ion conducting or protonconducting properties, inside the other phase which is the said matrix.

In the fourth aforementioned embodiment wherein in polymer-polymerincompatibility is used to form an ordered heterogeneous membrane thecasting solution may comprise a solvent or mixture of solvents, nonsolvents and surfactants or emulsifiers or coating agents which formsteric barriers between phases, a polymer, which will form the matrix ora mixture of two or more polymers which will form the matrix, a polymeror oligomers which contains ion or proton conducting groups in thebackbone and or as pendants or a combination of polymers and oligomerswhich contains groups which are ion or proton conducting in theirbackbone or pendants, and optionally other polymers which may act ascompatiblizers between the conducting polymer or polymers or only someof the conducting polymers or oligomers.

In one preferred embodiment of the fourth aforementioned embodimentthere is a co-solvent for two different polymers one of which will formthe matrix and the other will form the ion or proton conductingchannels. The one preferred case the proton conducting polymers will bethe minor component and the matrix will be the major component and bothpolymers will be incompatible with each other. For example the protonconducting polymer may be from 5 to 80% of the total weight of the finalmembrane in the more preferred case will be from 10 to 50% or from 10 to30% in order to achieve a combination of high flux and conductivity. Insolution the two polymers may be completely miscible within the solventmixture or in some cases they may be partially miscible. When thesolvent evaporates both components being incompatible with each otherwill begin to phase separate into a matrix rich phase and ion or protonconducting rich phase.

In another embodiment the ion conducting polymer is formed in thesolution containing the matrix polymer and the solvent. In this case thesolution contains polymers for the matrix, a common solvent, a monomerwith ion exchange or proton conducting groups, an initiator andoptionally a crosslinker.

The role of the matrix is to stabilize the ordered ion or protonconducting channels so that that they do not randomize after theelectric field is removed and especially in operation in a givenapplication. The matrix material also reduces the swelling of theconducting polymers enhancing selectivity. In a preferred case thematrix polymer will be water insoluble and have a low degree of swellingin water (preferably less than 20% and more preferred less than 10%),and in aqueous solutions or mixtures or solutions with other solvents orliquids or solutes such as alcohols, ethers, ketones, aldehydes acids,bases, oxidants and reductants. The matrix components may benon-crosslinked by covalent chemical bonds or crosslinked covalently.The crosslinking may occur during the formation or after the formationof the film. The matrix polymer may be a homopolymer or a co polymerwhich may be alternating or syndiotactic or isotactic or atactic. If thepolymers are block copolymers or random or alternative copolymers thedifferent monomers may have different groups. The groups on one type orall types of the monomers may have a structural role and may interactwith the other components in the film such as the proton conductingpolymers or networks. In general the matrix materials and polymersshould have relatively low dielectric constants as compared to theconducting polymers. The latter of which have ionic groups or protondonors ns proton acceptors. The matrix material may have polar groupssuch as of carbon halogen groups such as carbon fluorine being apreferred material. Other polar groups are aromatic ethers and ketones,and sulfones. The idea being that the particle or domain materials ascompared to the matrix material should have different dielectricproperties resulting in dielectric polarization of the particles ordomain in the external electric field with subsequent interactionbetween the dipoles leading to ordering of the phases in the directionof the applied field. The particle or domain forming materials should bechosen as to ensure phase separation with the matrix as the solvent isevaporating because of polymer-polymer incompatibility.

For the fourth aforementioned embodiment the proton or ionic conductingpolymer is preferably not soluble in water, water alcohol mixtures oralcohols, but may swell to different degrees. Alternatively the polymerthat is added to the solution may be soluble in water or various aqueoussolvent solutions and solvents but after it forms in the matrix it maybe crosslinked by covalent bonds, or a combination of polar andhydrophobic interactions with itself or with other components such asthe matrix or other polymers such as complexing polymers or polymersused to compatiblizers the conducting polymers and the matrix. Theproton conducting polymer may be a homopolymer or a co polymer which maybe alternating or syndiotactic or isotactic or atactic. The groups thatconduct ions or protons may be acid groups such as sulfonic, carboxylicsulfonamides, metal oxides such as silica oxide, zirconium oxidetitanium oxide, etc. Proton conducting groups may also be based onamines or ethers or amides or imines etc. If the polymers are blockcopolymers or random or alternating copolymers and the differentmonomers may have different groups. One of the monomers may have theproton conducting groups based on acid functions such as sulfonicgroups. Other groups may be present which may or may not facilitateproton or ion conductivity such as amine groups or other hydrogenbonding groups such as amines or ethers or amides or sulfides.Alternatively the other groups may be structural groups whose role is tostabilize the polymers against leaching or compatibilize the polymerwith the matrix.

For the fourth aforementioned embodiment the role of the matrix is tostabilize the ordered components of the ion or proton conductingchannels so that that they do not randomize after the electric field isremoved and during operation. This is especially the case for waterswelling and or water-soluble ion/proton conducting polymers. Suchpolymers may in addition be further stabilized by crosslinking betweenthemselves or by being covalently bonded to the matrix to form acrosslinked network. Other polymers which are water soluble arepreferably crosslinked after they are orders.

As the electric field is being applied and the solvent is beingevaporated and/or the solution is being cooled down and/or the melt isbeing cooled down it is preferred that matrix material as it is formingand does not adsorb most of the electrical energy which should go intoorienting the ionic or more polar conducting polymers and there domainsas they form due to polymer-polymer in compatibility with e the matrix.Crosslinking may be done by chemical additives or ionizing radiation orby heating under a vacuum to form crosslinks. Method of crosslinking:sulfonic groups are heated under vacuum at 150° C. for over night toform sulfone groups between polymer chains.

To enhance solubility of the conducting channels in the solvent orsolvent mixtures, the counter ion or polyelectrolyte may be chosen toenhance solubility. For example some of the cations of the sulfonicgroups may be in the H form or ammonium form, or the bases may be nonprotonated if polyamines are used. [For a list of conducting polymerswhich are incorporated into this patent by reference are found in “SolidPolymer Electrolytes by Fiona M. Gray 1991 VCH Publishers].

For the fourth aforementioned embodiment in addition to the matrixpolymers and materials and the ion/proton conducting polymers oroligomers other polymers or oligomers or low molecular weight additivesmay be present so as to facilitated ordering of the conducting polymersin the matrix, and/or compatibilize the conducting domains with theincompatible matrix and or to crosslink the conducting polymers afterthey are ordered or to crosslinked the matrix after film formation.Further additives may be added to enhance the conductivity of theconducting polymers. These additives may by LMW or intermediatemolecular weight or high molecular weight and may be proton donors orproton acceptors. The additive may also be used to enhance thepolymer-polymer incompatibility of the conducting polymer and domainscomposed of such polymers as they are formed

The solvent(s) in one preferred case should dissolve all the componentssuch as the polymer forming the matrix and the polymer which will formthe conducting domains, as well as any additional additives. Thedielectric constant of the solvent should be relatively low so that itdoes not prevent orientation of the conducting polymers or oligomers dueto adsorption of the electrical energy of the applied filed but itshould be sufficient to dissolve polar polymers and even ionic polymers.It may be in some cases that to dissolve the components of the membranea mixture of solvents need to be used to achieve the required solubilityparameters suitable for all the components. The boiling point of thesolvent may be from RT to 300° C. though the preferred case would bebetween 40 to 220° C. Some preferred solvents are NMP, DMF, THF,Acetone, toluene, toluene/alcohol mixtures, alcohols such as ethanol,propanol, butanol and their isomers. Substantial conductivity of thesolvents is determined to the process as this drastically reduces thefield strength inside the membrane or might cause over heating. It istherefore highly preferable to use non-polar solvents whereas the polarsolvents should be dry.

Non solvents may be added to increase the solubility of one componentwhile it may reduce it for the other component. For example the solventswhich dissolve the highly non polar matrix may not dissolve the polarconducting polymer and in this case a small amount of a polar solventmay be added. If two or more solvents are added with different solvatingpowers then as one of the solvents is evaporated faster than the othersolvating power of the mixture changes and may improve or it maydecrease giving different types of domain formation inside the matrix.

The components of the solution may be completely miscible or partiallymiscible giving partial separation of phases, partial separation or onlyone phase. This is a function of the solubility power of the solvent andor solvent/non-solvent mixtures and the temperature of the solution atwhich the evaporation is being carried out. Also the nature of the finalfilm formed depends on the history of the solution. Solutions which areprepared at elevated temperature are stirred and optionally heated toachieve a uniform solution. Upon standing at lower temperature suchsolution may form separate phases as indicated by cloudiness orprecipitation. Thus the time the solution is cast after it is preparedis important in determining the nature of the domains formed inside thefilms. Since the wet film is in contact with the electrodes or with thesolvent environment solvent which can under readily oxidation reductionreactions, such as water are not desirable in large quantities, but maybe tolerated in smaller quantities. The viscosity of the solution mayvary from free flowing solutions to highly viscose pastes that have tobe applied to the electrode (s) by extrusion.

The wet film thickness will depend on the thickness of the final driedfilm, and the concentration of the components in the solution. Typicalconcentrations of 5 to 35% solids should be cast at 500 microns to 30microns in order to form a dry film of less then about 100 microns andpreferably in the range of less than 50 microns. For self standingmembranes the thickness will depend on the selectivity of the membraneand reduction of flux across the membrane of feed components such as forexample hydrogen or methanol in fuel cell applications, or to enhanceselectivity between ions in membranes used for electro-dialysisapplications. In state of art fuel membranes such as Dupont's Nafion,thicker membranes have to be use to limit crossover than about 200 to150 microns maybe used if the conductivity of the membrane for thedesired component in the feed such a adsorption is high enough. It isdesired to have thin membranes and its one of the advantages of thisinvention is that highly selective thin membranes can be made becauselower concentration of conducting polymers would be used, that wouldotherwise reduce selectivity. Such thin membrane may also improveconductivity.

Processing the solution before casting or before application of theelectric field can be used to adjust the final morphology of the protonconducting domains in the matrix. If the solution is heated beforecasting then the solution may be more homogenous and when the field isapplied and evaporation started and slower domain formation occurs.Alternatively if there is some evaporation and the solutions is broughtcloser to phase separation then other domain morphologies will occur. Inaddition the solution may be cooled to initiate phase separation thenthe electric field is applied and evaporation is carried out.

Hot melts where the melt polymer is the solvent and dissolves theconducting polymers. Instead of solvents the matrix material may bemelted at elevated temperature and into this melt additional materialsuch as the conducting polymer may be dissolved. When the melt isextruded or otherwise formed into a membrane film it is cooled and theconducting polymer forms a second domain compared to the matrix polymersbecause of phase incompatibility.

Mode of Evaporation for Solvents or Temperature Reduction Scheme:

In one preferred mode of membrane or film formation is to cast a wetfilm at room temperature, apply an electric field across the membrane,and evaporate the solvent under stream of inert gas. Another mode is tocast the wet film, apply the electric field and evaporate the solventunder a stream of inert gas without raising the temperature. The streamof inert gas may be substituted by a vacuum in some cases underconditions which do not form bubbles in the membrane.

Electrodes and Their Configuration

The electrodes can be flat and the wet or molten film is placed inbetween the said electrodes to form a flat oriented film. In one casethe wet film is cast onto the surface of one of the electrodes andpassed under the second electrode with a small air gap. In another casethere is no air gap and both electrodes are making contact with a givenside of the wet or molten film. If the electrodes are placed on a moltenfilm which will be cooled then both electrodes may be dense with verylow vapor or gas transmission. Or the electrodes may be porous if thepore size and hydrophobic/hydrophilic balance is such that there islittle penetration of the molten material into the depth of theelectrodes. If the electrodes are placed on a wet film which requiressolvent removal then the bottom electrode upon which the wet film iscast may be dense with very low vapor or gas transmission, or it may beporous if the pore size and hydrophobic/hydrophilic balance is such thatthere is little penetration of the wet film into the depth of theelectrodes. The top electrode if it does not contact the surface of thewet film, may be either dense or porous or may be a net. If it is placedon the surface of the wet film and evaporation of the solvent from thefilm is required then it should be porous electrode or a net and floaton the surface of the film. In another embodiment the electrodeconfiguration may be a cylinder in which an extruded hollow fiber ispassed and this cylinder forms one electrode, and the other electrode isa wire going through the lumen of the fiber. The outer cylinder maycontact the outer surface of the extruded HF. The solvent from the wetfilm is evaporated through the outer surface and the porous electrodewhich is the outer cylinder or through inert gas flow threw the fiber slumen. If the HF is molten then a solid membrane may form by cooling.

Another preferred electrode arrangement is two electrodes with themembrane resting on one electrode and an air gap between the secondelectrode and the film surface. Resting on the top surface of the wetfilm of molten film may be a conductive net or porous plate which willfloat on the surface. This conductive net or plate in contact with thefilm surface then becomes the second electrode. In this configurationthe electrodes may be separated form the membranes or may be a permanentpart of the membrane.

Distance Between Electrodes

If the electrodes are placed on either surface of the wet or molten filmthen their distance will be that of the initial thickness of the wet orfluid film and molten layer and this distance will decrease as thesolvent is evaporated from the wet film or as the molten film is cooled.In general the wet/fluid or molten film will have a thickness from 10 to1000 microns and preferably 20 to 500 microns and most preferred between20 to 200 microns. Thus the distance of separation of the electrode isthe thickness of the film the electrodes are contacting. If there is anair gap then the distance between the electrodes is the thickness of theair gap and the membrane. Air gaps of up to 2 mm can be used and if themembrane thickness is only 0.1 mm then part of the total voltage dropwill fall on the air gap and the field in the solution or melt will bereduced. In that case the applied voltage should be larger.

The space gap may have flowing gas which is inert in the electric filedto facilitate removal of the solvent. The gas may be dry nitrogen, argonor neon. Dry gas is preferable to gas with water vapor To a lesserextent dry air may be used at low voltage. In some cases when thesolvent has a low boiling point a stagnant non flowing inert gas may bepresent open to the environment.

Temperature and Time of Wet Film Driving:

When the electric filed is applied across the wet film then sufficientheat is applied to remove the solvent, together with a flowing stream ofgas or in some cases without a flow of gas, or in the presence of avacuum. For a solvent with a low boiling point the temperature may bekept at ambient conditions with flow gas. Low boiling solvents will notbe kept in a vacuum because of bubbling. In the case of a molten filmthen the temperature of keeping the material in the molten state will beselected. For example, between 70 to 200° C. The electric filed isapplied and the temperature may be reduced at different rates. In somecases the high temperatures will be kept for an extent period and thenslowly drop or in other cases it will drop rapidly to a given level.

The membrane thickness may be between 5 to 500 microns, preferablebetween 10 to 150 and most preferred less than 100 micron to give higherconductivity consistent with mechanical strength. The films may beself-supporting or they be further reinforced by a net fiber orsupported on a porous support. The porous support may be symmetric orasymmetric with respect to pore size from one side to the other-side.The pore size may be characterized as MF, UF or NF as is well known inthe state of art. In one preferred embodiment the ordered film on theporous support is on the side with the smaller pores.

Domain Shape and Size of Conducting Channels:

The conducting or permeating domains are formed by the by phaseseparation under an electric field. These domains aggregate to formconducting channels within the matrix. The morphologies and shapes ofthe individual domains and their aggregates may be as irregular shapedparticle, fibers or regular shaped particles such as spheres, tubules,plates, helices, ribbons, or any combination of these configurations orshapes. Size of the domains may range from a few molecules to severalmoles. In terms of size they may have effective diameters of 1 nanometerto microns and millimeters. In the case of fibers fiber length they maybe 10 nm to millimeter lengths with diameters of 1 nanometer to severalhundred nanometers. In some cases small domains may aggregate to formconducting channels, wherein the domains that aggregate may have thesame approximate shape and size or in other cases different shapes andsizes.

In the aforementioned first embodiment, wherein ion exchange particlesare dispersed in a polymer melt or liquid at elevated temperature,formed into a membrane, oriented in an electric field and then cooled toform the conductive membrane, the membrane matrix material may be takenfrom thermoplastic or thermo-elastomers. These comprise polymers thatare solid at the temperature of use but may be molded at elevatedtemperatures, above which they may convert into the liquid crystallineor thermo-elastic state, which will flow under pressure. Some suchmaterials are polyolefins and polyolefin ionomers (polymers containing alow level of ionic groups in the hydrocarbon backbone), thermoplasticelastomers and thermoplastic condensation polymers.

Non-limiting examples of materials which may be used in this inventionas the matrix material in embodiments 1, 3 and 4 are:

Polyethylene and polypropylene copolymers with melting points from 60 to200° C., but preferably from 70 to 130° C. Some examples arepolyethylene of low and medium density with Tm between 90 to 130° C. andpolyethylene with mp between 90 to 130 C and melt viscosity 0.1 to 80poise, polyethylene co- or ter-polymers with monomers such as 1-butene,hexene, butyl acrylates and butylacrylate-co-carbon monoxide,polyethylene ionomers especially those based on polyethylene copolymerswith carboxylic groups or such as acrylic acid, and/or methacrylic acid,maleic acid. Examples of such polymers are metal salts ofpolyethylene-co-methacrylic acid, maleated ethylene-propylene-dienerubber, maleated high-density polyethylene, maleated polypropylene,polyethylene-co-acrylic acid and carboxylated acrylonitrile-butadienerubber, and carboxylated nitrile rubber. The counter ions of theaforementioned polymers may be chosen from a range of cations. Someexamples of cations are H+, Na, K, Li and Zn.

Non-ionic thermal plastic elastomers and plastics such aspoly(butadiene-co-styrene) polymers and ethylene copolymers with1-butene, vinyl acetate and ethyl acrylates.

Other thermal plastics which may be used in this invention are:ethylene-propylene and its copolymers, such as styrene acrylonitrile,acrylonitrile-butadiene-styrene copolymers, and styrene-alpha-methylstyrene copolymers, polyvinyl chloride and copolymers such as vinylchloride-vinylacetate, vinyl chloride acrylonitrile and vinyl chloride,vinylidene chloride, vinylidene chloride and its copolymers withacrylonitrile and acrylates, and methyl methacrylate.

Under condition where high temperatures can be applied to melt thepolymers forming the matrix then the following can be used:polyinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyhexafluropropylene (PHFP), polychlorotrifluoroethylene (PCTF), and coand terpolymers of the above, polysulfone, polyether sulfone,polyphenylene sulfone, polyether ketone, polyether ether ketone, andother variations of polyether ketones and polysulfones, polyphenylenesulfide, phenylene sulfone and variations of sulfide and sulfone in thesame polymer, polyether based on polyphenylene oxide such as 2,6dimethylphenylene, aromatic polyether imides, polyether imide-amide,aromatic polyamides and aromatic aliphatic polyamide combinations.

The above polymers may be used in the aforesaid first and fourthembodiment as the matrix polymer and many of them are soluble insolvents at room temperatures and may be used in the aforesaid thirdembodiment.

In the said second and different aspects of the fourth embodiment,wherein for the second embodiment the ion exchange particles may bedispersed or in the fourth embodiment where the ionic or conductingpolymer may be dissolved, in a viscose liquid of monomers, or reactiveoligomers or polymers, at room or elevated temperature, formed into amembrane configuration, the ion exchange particles added (secondembodiment) or the domains formed by polymer-polymer incompatibility(fourth embodiment) are oriented in an electric field; wherein thecomponents of the solution undergo reaction during the time the electricfield is applied to form a solid matrix the oriented particles ordomains fixed within the matrix, the membrane matrix material may bechosen from room temperature crosslinking and thermoset materials suchas epoxies, silicones, acrylates, etc.

Examples of such thermoset materials are vinyl monomer systems thatpolymerize and crosslink through their radicals. Various monomers canundergo polymerization in the presence of initiators. When amultifunctional monomer is included, crosslinking will occur and resultin a stable matrix. Different initiators can be used, which beginpolymerization at room temperature upon their addition to the monomersolution or are activated at elevated temperatures. Still other systemscan contain monomers, which can undergo thermal polymerization withoutcrosslinkers.

An example of a system, which undergoes spontaneous thermalpolymerization, is styrene to polystyrene. If the crosslinkerdivinylbenzene is included in the mixture then a crosslinked matrix willresult. These polymerizations can be carried out in the bulk or insolution with a common solvent. These and other thermo-polymerizingsystems are part of the invention.

Low molecular weight hydroxy-terminated polydimethylsiloxanes maybe beconverted to rubber-like products by reaction with alkoxy silanes suchas tetraalkoxy silanes, trialkoxy silane and polyalkoxysiloxane. Bychoice of catalyst cure may be effected at room temperature in timesranging from 10 minutes to 24 hours.

Another approach to achieving crosslinked products fromsilanol-terminated gums is the cure of polysiloxanes containing silanichydrogen. This reaction requires the presence of metalloic salts.

Epoxy condensations may be used as membrane matrix materials. Theyinclude three major types 1-cycloaliphatic epoxy resins, epoxidizedoils, and glycidyl resins. Epoxy resins based on bus phenol A andepichlorohydrin are the most commercially useful resins.

Polyamides and derivatives such as polyamidoamines are used as curingagents instead of polyamines to achieve special properties such as lowertoxicity improved flexibility longer pot life lower exotherm. The curingis not due to amide groups, but rather to secondary amine and terminalamine groups.

Polyaddition can be carried out with phenols and thiols. Phenols areprimarily used to make HMW epoxy resins by reaction with bisphenol A anddiglycidyl ethers of bisphenol. There are two reactions: 1) phenol withthe epoxy and 2) hydroxyl group generated from the epoxide-phenol withanother epoxide.

Like phenols, thiols react with epoxy groups to form hydroxy sulfides.In the presence of suitable catalysts the epoxy-thiol reactions areseveral times faster than epoxy amine reactions particularly at lowtemperatures. The reactions are very selective without side reactions.The reaction can be accelerated in the presence of amines and twoalternative reaction routes have been suggested to explain the formationof sulfide ions intermediates, which then reacts with the epoxy.

Curing can be carried out with amino resins, which comprise mainlyurea-formaldehyde (UF), melamine-formaldehyde, guanamine-formaldehydeusually prepared by hydroxymethylation of urea, melamine, orbenzoguanamine.

A phenol-formaldehyde resin formed from an excess of formaldehyde iscalled a Resol and that formed an excess of phenol is called a Novalac.Resols are a mixture of monomeric and polymeric hydroxymethylphenolsmade under basic conditions.

Thermosetting Acrylic Resins (TSA) have the advantage that the polymercan be made with different functional groups, which can then be curedwith several different curing agents and provide specific propertiessuch as controlled crosslinking density. These functional groups can becarboxyl (acrylic acid methacrylic acid itaconic acid) epoxide groups(glycidyl acrylates, glycidyl methacrylate, allyglycidyl ether), amines(dimethylaminoethylmethacrylate, vinyl pyridine, t-butylaminoethylmethacrylate, anhydrides (maleic anhydride, itacanoic anhydride)hydroxyl groups (allyl alcohol, hydroxyl-methyl methacrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate) amide (acrylamide,methacrylamide, maleamide) amide derivatives (N-hydroxymethylacrylamide, etc) isocyanates (vinyl isocyanates, allylisocyanates). Acrylate monomer crosslinker methyl acrylamidoglycolatemethylether has a vinyl group for polymerization and an activated methylester and a methyl ether. The latter group can be crosslinked withamines at RT or with alcohols under acid catalysis. This monomer isdesigned for RT cure coatings without the use of toxic isocyanates andacid cure coatings without formaldehyde release.

Moisture curing system based on isocyanate-oxazolidine chemistry forvarious TSA systems such as alkyd-MF (melamine formaldehyde), acrylicpolymer-epoxy, acrylic-MF, hydroxymethylamide-acrylic, urethane-acrylic.The acrylic polymer-epoxy combination has the best chemical resistanceand good toughness.

Materials cross-linked through auto-oxidation can also be used. In theaforesaid third embodiment, in which the ion exchange particles aredispersed in a viscose liquid comprising a polymer dissolved in asolvent, formed into a membrane configuration, oriented in an electricfield wherein the solvent is evaporated during the time the electricfield is applied to form a solid matrix, the oriented particles beingfixed within the matrix, the following matrix materials may be used:

Fluorinated polymers which may be used as matrix materials in thisinvention are: polyinylidenefluoride (PVDF), polytetrafluoroethylene(PTFE), polyhexafluropropylene (PHFP), polychlorotrifluoroethylene(PCTF), and co- and ter-polymers of the above, such as PVDF-co-PTFE,PVDF-co-PTFE, PVDF-co-PHFP, PVDF-co-PCTF, Poly(perfluoroalkyl dioxides)as a homopolymer and copolymers with other fluorinated monomers such asvinylidene fluoride or tetrafluoroethylene.

Other materials that can be used are those known as engineeringplastics, especially those made using condensation polymerization, forexample, polysulfone, polyphthalimidazole, polyether sulfone,polyphenylene sulfone, polyetherketone, polyether ketone, polyetherketone ether ketone, and other variations of polyether ketones andpolysulfones, polyphenylene sulfide, phenylene sulfone and variations ofsulfide and sulfone in the same polymer, polyethers based onpolyphenylene oxide such as 2,6 dimethylphenylene, aromatic polyetherimides, polyether amide-amide, aromatic polyamides and aromaticaliphatic polyamide combinations, polybenzimidazole, halomethylatedderivatives of the above polymers on the aromatic or aliphatic groups.

Many different solvents can be used and can be chosen from halogenatedhydrocarbons, fluorinated hydrocarbons, alcohols, esters amines, lactams(N-methylpyrrolidinone), lactones, amides (dimethylformamide, dimethylacetamide), ethers, dimethylsulfoxide, etc. These solvents may be usedto dissolve many of the aforementioned polymers and such solutions maybe used in the aforesaid third embodiment. In summary the matrixmaterials, and solvents described for the third embodiment may also beused as matrix and solvent material for the fourth embodiment.

The conducting polymers or oligomers for embodiment 4 of this inventionmay be chosen the ionic or polar derivatives: a) completely fluorinated(perfluorinated) polymers or b) partially fluorinated or polymers or c)non-fluorinated. In one preferred case the conducting polymer is madefrom sulfonated fluorocarbon polymers. Examples of different conductingpolymers are:

1) Polymeric materials such as sulfonated polyetherketones, polysulfonesand polyethersulfones, sulfonated polyphenylene oxide and graftpolymerization (ex polytetrafluoroethylene ofpolyethylene-co-tetrafluoroethylene or PVDF with grafted polystyrene.Plasma polymerization (ex. perfluorinated compounds such asfluorobenzene followed by sulfonation, phosphorylation or carboxylationor plasma polymarization of phosphonic acid with tetrafluoroethylene

In general cation exchangers based on sulfonic acid also included arehowever cation exchange polymers based on other groups (e.g. —PO2H2,—CH2PO3H2, —COOH, —OSO3H, —OPO2H2, —OPO₃H2, —OArSO3H) and those basedanion exchange membranes based on amino and quaternary ammoniums.

Copolymers of tetrafluoroethylene with perfluorinated sulfonic acidpolymer membranes of the same type. For example

Where n is 0 to 2 and m is 2 to 5

2) Polymeric materials such as sulfonated Polyphenylene sulfides,polyetherketones, polysulfones and polyethersulfones,polyphenylquinoxiline, sulfonated block polymers(polystyrene-ethyelen/butylene-styrene which forms sulfonated domainsanother example of which is sulfonated Kraton). Variations of thesulfonation procedure where in the monomer of polysulfone is firstsulfonated and the sulfonic groups are on the sulfone moiety rather thanthe aromatic ether. Cation exchange polymers made from sulfinated andsulfonated polysulfonaes and polyether sulfones poly(trifluorostyrene)ionomers

3) Mixed groups on a chain aromatic polymers which have been nitratedand the sulfonated to make cation exchange polymers. The nitro groupsmay be optionally reduced to amines.

4) Polymers of grafted sulfonated beta trifluorostyrene in a PTFE-HFPmatrix, polyvinyl alcohol with sulfonated polystyrene.

5) Polymers made by plasma polymerization (ex. perfluorinated compoundssuch as fluorobenzene followed by sulfonation, phosphorylation orcarboxylation or plasma polymarization of phosphonic acid withtetrafluoroethylene)

6) Hybrid organic inorganic membranes made of a polymer or matrix ofmaterials with proton conducting inorganic particles formed when asoluble non crosslinked inorganic material [e.g., zirconium phosphate,heteropolyacids for example phosphoatoantimonic acid] or precursor tosuch inorganic particles such as for zirconium oxide, zirconiumphosphate, titanium oxide, aluminum oxide, silica, is dissolved in thecommon solvent with the polymer matrix.

7) The following polymers with sulfonic phosphonic or boronic acidgroups chosen from polyheterocyclics such as polybenzimidazole,polyoxazoles, polypyridines, polypyrimidines, polyimidazoles,polythiazoles, polybenzoxazoles, polyoxadiazoles, polyquinolines,polyetherketones polyethersulfones and polyphenylquinoxalinesPerfluorinated sulfonic membranes.

8) Sulfonated substituted and non substituted trifluorostyrene basedpolymers Radiation grafted FEP (perfluoroethylene-perfluoropropylenecopolymer) or polyethylene-alt-tetrafluroethylene (ETFE) with styrenefollowed by sulfonation. Sulfonated random copolymer ofstyrene-butadiene and sulfonated triblock polymer ofstyrene-ethylene/butylene-styrene; Sulfonated triblock polymer ofstyrene-ethylene/butylene-styrene; Sulfonated polyarylene sulfidesulfones and polyarylene sulfones, polyarylene sulfide sulfones andpolyarylene sulfones, sulfonated polystyrene copolymerized withtetrafluoroethylene, Sulfonated polystyrene, polyethylene acrylicsmethacrylics, perfluorosulfonic polymers; Sulfonated polyphosphazenespolymers.

The sulfonation of the block copolymers is carried out such that itoccurs preferentially on only one of the blocks. For example, in thecase of triblock polymer of styrene-ethylene/butylene-styrene, thesulfonation may be only on the aromatic groups of styrene, e.g., apolystyrene-block-polyethylene-ran-butylene)-block-polystyrene,sulfonated [29 wt. % styrene where 45-55% of styrene units aresulfonated] produced by Aldrich Chemical Company Catalog No. 44,888-5)

9) Aryl polymers-sulfinated sulfonated and aminated polysulfonepolyether sulfones. Phosphoatoantimonic acid in sulfonated polysulfonesolution; Polymers based on bis[perfluoroalkyl)sulfonyl]imides.

Polymers by nitrating PES PSu PEEK and optionally reducing the nitro toamines then sulfonating, Sulfonated Kraton materials, Highly sulfonatedpoly(thiophenylene)

10) Polyethylene ionomers especially those based on polyethylenecopolymers with carboxylic groups or such as acrylic acid, and ormethacrylic acid, maleic acid. Examples of such polymers are metal saltsof polyethylene-co-methacrylic acid, maleated ethylene-propylene-dienerubber, maleated high-density polyethylene, maleated polypropylene,polyethylene-co-acrylic acid and carboxylated acrylonitrile-butadienerubber, and carboxylated nitrile rubber. Wherein the ionic monomercomprises from 2 to 20% wt % of the copolymer, Sulfonated elastomericionomers such as copolymers of 2-butylstyrene sulfonate and isoprene,copolymer of sodium styrene sulfonate and isoprene, sulfonatedisobutylene isoprene copolymers, sulfonated ethylene propyleneterpolymers [such as sulfonated ethylene-propylene-diene rubber], andsulfonated styrene or butadiene styrene block copolymers. The waterinsoluble sulfonated polymers may have sulfonic groups in the range of0.04- to 2-meq/gr polymers and preferable 0.1 to 1 meq/gr. The counterions of the aforementioned polymers may be chosen from a range ofcations. Some preferred cations are H+, Na, K, Li and Zn.

EXAMPLES

The following examples of embodiments of the invention are intended tobe illustrative and not limitative.

Example 1

Membrane samples of different cation exchange resin content wereprepared by using quantitaties of matrix precursor (two componentsilicon rubber-RTV) and cation exchange resin powder made of sphericalparticles 30-40 μm in diameter according to the following Table IV:

TABLE IV Resin Content Matrix Precursor (gr) (W %) Component A ComponentB Resin Powder (gr) 10 0.811 0.089 0.1 15 0.772 0.078 0.15 20 0.7270.073 0.2 30 0.636 0.064 0.3 40 0.545 0.055 0.4 50 0.455 0.045 0.5

The components were mixed together and the viscous mixture was pouredinto the membrane preparation form described in FIG. 1. The cell wasclosed with the upper electrode module and a 50 Hz AC electric field ofstrength of 860 V/cm was applied between the electrodes for 4 Hrs atroom temperature. The cell was then opened and the cured membrane takenout and equilibrated in 0.1 M KCl solution. The same procedure wasapplied to a second preparation but without the electric field. Theconductivities of the ordered and non-ordered membranes were measured ina standard cell used for this purpose. It was found that the orderedmembranes carry a much higher specific conductivity with respect to thenon-ordered ones. The results are shown in FIG. 2 a.

Example 2

The same procedures as in example 1 were applied to a 200 to 270 meshcation exchange powder with non-spherical particles. The results aredepicted in FIG. 2 b, with significantly improved conductivity for theordered membranes compared with the non-ordered ones.

Example 3

The same procedures as in Example 1 and 2 are applied to powders made ofspherical and non-spherical anion exchange resins. As in the previousexamples, the ordered anion exchange membrane thus obtained have a muchlarger specific conductivity as compared to the random ones.

Example 4

In the above procedures, the a-priori liquid silicon rubber was replacedby low density polyethylene flakes melted at a temperature above 120° C.and mixed by some standard methods with a cation or anion exchangepowders in spherical and non-spherical shapes. AC electric fieldsstrengths in the range 300 to 2000 V/cm were applied to the melt thatwas cooled gradually in a period of 2-6 Hrs. The specific conductivitiesof the membranes thus prepared were compared to random membranesprepared with the same materials but without the application of anelectric field. As in the previous examples, the ordered membranes showa much higher specific conductivity as compare to the random membranes.

Example 5

Example 4 was repeated using a powder, in a pellet configuration, of thecopolymer poly(ethylene-co-acrylic sodium salt), where in the acidcomponent was 5 wt % acrylic acid, having a Tm (DSC) 98° C. instead ofthe low density polyethylene, with cation exchange particles. As in theprevious example, the ordered membranes showed a much higher specificconductivity, compared to the random membranes.

Example 6

Preparation of an ordered proton conducting membranes. The matrix of themembrane is polyvinylidene fluoride (PVDF)[Tm 165-170, Average Mn of71,000 purchased from Aldrich Catalog No. 42,715-2] and the protonconducting materials are of phosphotungistic acid (PTA). PVDF films arenon-permeable to methanol and PTA is a well-known proton conductor. 15grams of PVDF are dissolved in 85 grams of 1-methyl-2-pyrrolidionone.

To this solution, 5.2 grams of PTA (34% of PVDF) were added and mixedhomogeneously into the polymer solution. The mixture was then cast on aTeflon plate and dried at 70° C. in a convection oven to give a 100micron thick membrane. This membrane was then placed between twoelectrodes of configuration, as described in Example 1 and placed in achamber which was flooded with argon and heated 160° C. for 0.5 hourswith 20 volts applied across the membrane. After two hours, the heatingwas stopped and the system allowed cooling to room temperature with theapplied voltage still on. The proton conductivity of this membrane wassignificantly higher compared to a membrane made exactly the same waywithout the applied field.

Example 7

Preparation of an ordered proton conducting membranes by the ordering ofphase separated domains (Embodiment 4).

All the polymeric materials are dried overnight at 80° C. in a vacuumoven. The matrix of the membrane is 15 grams of polyvinylidenefluoride-co-hexafluoropropylene (PVDF-co-HFP)[Tm 155-160, Average Mn of110,000 and 5.2 grams of the proton conducting polymer sulfonatedpolysulfone in the hydrogen form with a capacity of 1.6 meq/gr aredissolved in 85 grams of 1-methyl-2-pyrrolidionone.

The solution was then cast as a 0.5 mm wet film on a graphite electrodeof 10 cm² area. Over this another graphite electrode was placed at aheight of 1.0 mm leaving a space gap of 0.5 mm. The electrode systemwith the wet membrane was placed in an oven at 70° C. with a stream ofdry argon flowing through the space gap between the top electrode andthe surface of the wet film. Across the electrode system 200V at 50 HzAC was applied for 12 hours to evaporate the solvent and form a solidmembrane. The heating was stopped and the system allowed cooling to roomtemperature with the applied voltage still on. The proton conductivityof this membrane was significantly higher compared to a membrane madeexactly the same way without the applied field.

Similar results were also obtained using a vacuum rather than a streamof dry Argon to evaporate the solvent.

When the above procedure is repeated while the proton conducting polymerwas sulfonated polyethersulfone in the hydrogen form with a capacity of1.8 meq/gr made by the procedure described in Example 6 of U.S. Pat. No.4,508,852, and the solvent evaporated under a vacuum, the resultingmembrane showed a proton conductivity which is significantly higher thanof a membrane made exactly the same way without the applied field.

When the above procedure is repeated while the proton conducting polymerwas sulfonated triblock polymer ofpolystyrene-block-polyethylene-ran-butylene)-block-polystyrene,sulfonated [29 wt. % styrene where 45-55% of styrene units aresulfonated] produced by Aldrich Chemical Company Catalog No. 44,888-5)in the hydrogen form and the solvent evaporated under a vacuum, theresulting membrane showed a proton conductivity which is significantlyhigher than of a membrane made exactly the same way without the appliedfield.

Example 8

Example 7 is repeated wherein the solution was then casted as a 0.5 mmwet film on a graphite electrode of 10 cm² area. Over this anothergraphite electrode was floated on the surface of the wet film. Theelectrode system with the wet membrane was placed in an oven at 70° C.with a stream of dry nitrogen flowing through the oven. Across theelectrode system 200V at 50 Hz was applied for 12 hours to evaporate thesolvent and form a solid membrane. The heating was stopped and thesystem allowed cooling to room temperature with the applied voltagestill on. Like in example 7, the proton conductivity of this membranewas significantly higher compared to a membrane made exactly the sameway without the applied field.

Example 9

Example 1 is repeated using nanosized silica particles, instead oforganic ion exchange particles. The membrane made under an electricfield had higher conductivity than the membrane without the appliedelectric field.

While embodiments of the invention have been described by way ofillustration, it will be understood that the invention may be carriedout with many variations, modifications and adaptations, withoutdeparting from its spirit or exceeding the scope of the claims.

1. Process for producing ion exchange membranes, which comprises thesteps of: a) providing a matrix material, comprising a polymericcomponent chosen from the group consisting of monomeric and oligomericpolymer precursors and cross-linkable polymers; b) introducing in saidmatrix ion cation or anion exchange particles, or proton or hydroxyl orion conducting particles or any combination thereof; or cation or anionexchange polymers, or proton or hydroxyl or ion conducting polymers, orany combination thereof; c) mixing said particles or dissolving saidpolymer of step (b) with said matrix, wherein said particles or saidpolymers are used in amounts from 20 to 40 wt % of the combined amountof said matrix, and said particles or polymers; d) forming the resultingmixture into membrane configuration; e) ordering by an electric fieldsaid particles or ordering by an electric field the domains of saidpolymer formed by polymer-matrix phase separation upon solventevaporation or cooling, wherein said electric field has intensity from50 to 20,000 V/cm; and f) if said matrix comprises or consists of apolymer precursor or a cross-linkable polymer, said precursor is curedconcurrently with said ordering of said particles, or if the matrixcomprises a polymer solution or polymer melt the said polymer solutionis evaporated or the said polymer melt is maintained and then cooledconcurrently with said ordering of said particles; wherein the resultingmembrane thickness is between 10 to 500 microns.
 2. Process according toclaim 1, wherein the matrix material comprises or consists of a polymer.3. Process according to claim 1, wherein the matrix material comprisesor consists of a polymer precursor.
 4. Process according to claim 3,wherein the polymer precursor is cured concurrently with said orderingof the ion exchange particles.
 5. Process according to claim 1, whereinthe introduction in the matrix of the ion exchange particles and themixing of said particles with said matrix are carried out concurrently.6. Process according to claim 2, wherein said polymer is homogeneouslymixed with ion exchange particles either at elevated temperatures orwhen dissolved, and wherein said polymer is chemically resistant inacids and/or bases and/or oxidants.
 7. Process according to claim 3,wherein the polymeric matrix is a material homogeneously mixed with ionexchange particles or polymers when not yet cured at elevatedtemperatures or when dissolved, and when cured a polymer is formed thatis chemically resistant in acids and/or bases and or oxidants. 8.Process according to claim 1, wherein the polymeric matrix is chosenfrom the group consisting of polyethylene, polypropylene and polyamides.9. Process according to claim 1, wherein the polymeric matrix is chosenfrom the group consisting of polyvinyl halogenated homo polymers, orcopolymers, block-co- or tri-polymers or grafted polymers andengineering plastics.
 10. Process according to claim 9, wherein thepolyvinyl halogenated polymers are chosen from the group consisting ofpolyvinylidenefluoride (PVDF), PVDF copolymers, polyvinylidene chloridecopolymers and polyvinyl chloride copolymers, polytetrafluoroethylene(PTFE), polyhexafluoropropylene (PHFP), polychlorotrifluoroethylene(PCTF), and co- and ter-polymers of the above, such as PVDF-co-PTFE,PVDF-co-PTFE, PVDF-co-PHFP, PVDF-co-PCTF, poly(perfluoroalkyl dioxides)as a homopolymer and copolymers with other fluorinated monomers such asvinylidene fluoride or tetrafluoroethylene.
 11. Process according toclaim 1, wherein the ion exchange particles are chosen from among porousand non-porous particles and have an ion exchange capacity of 2 to 5meq/g (dry basis) for the cation exchanges and of 1 to 3 meq/g (drybasis) for the anion exchangers.
 12. Process according to claim 1,wherein the ion exchange particles have diameters from 0.2 to 200microns.
 13. Process according to claim 12, wherein the ion exchangeparticles have diameters from 20 to 50 μm.
 14. Process according toclaim 1, wherein the ion exchange particles are in the nano-size range.15. Process according to claim 1, wherein the ion exchange particles arespherically shaped beads.
 16. Process according to claim 1, wherein theion exchange particles are fibers, platelets or irregular shapedparticles.
 17. Process according to claim 1, wherein the ion exchangeparticles are in the form of a powder made of ground particles. 18.Process according to claim 1, wherein the electric field has intensityfrom 800 to 1500 V/cm.
 19. Process according to claim 1, wherein theelectric field is an alternating field.
 20. Process according to claim19, wherein the electric field has a frequency from 5 to 2000 Hz. 21.Process according to claim 20, wherein the electric field has afrequency from 20 to 150 Hz.
 22. Process according to claim 1, whereinthe electric field is a DC field.
 23. Process according to claim 1,wherein the electric field is applied for periods up to 10 hours. 24.Ion exchange membranes, according to claim 1, comprising a polymermatrix and ion cation or anion exchange particles, or proton or hydroxylor ion conducting particles; or any combination thereof; or domains ofcation or anion exchange polymers, or proton or hydroxyl or ionconducting polymers, or any combination thereof wherein said domainsoccurred by matrix polymer incompatibility, and wherein said particlesor domains are generally ordered, wherein said membranes are optionallyion conducting membranes.
 25. Ion exchange and ion conducting membranesaccording to claim 24, wherein the matrix comprises a material chosenfrom the group consisting of polyethylene, polypropylene, polyamides,polybenzimidazole, polysulfones, polyether sulfones, polyvinylidenefluoride, polyvinylidene fluoride copolymers, polyvinylidene chloridecopolymers and polyvinyl copolymers; wherein the ion exchange andconducting particles or domains have an ion exchange capacity of 0.5 to5 meq/gr (dry basis) for the cation exchanges and of 1 to 3 meq/g (drybasis) for the anion exchangers, the diameters or the shortest dimensionof which, are ranging from 0.002 to 200 microns, and their amounts arefrom 10 to 70 wt % of the membrane.
 26. Ion exchange and ion conductingmembranes according to claim 24, having a configuration chosen from thegroup consisting of flat, tubular, capillary, or hollow fiberconfigurations.
 27. Ion exchange and ion conducting membranes accordingto claim 24, having an improved passage of protons and a greaterselective passage of protons compared to methanol or hydrogen gascompared to membranes wherein the particles or domains are not ordered.28. Process according to claim 1, wherein the polymeric matrix is chosenfrom the following group of polymers, made by condensationpolymerization: polysulfone, polyphthalimidazole, polyether sulfone,polyphenylene sulfone, polyether ketone, and other variations ofpolyether ketones and polysulfones, polyphenylene sulfide, phenylenesulfone and variations of sulfide and sulfone in the same polymer,polyethers based on polyphenylene oxide such as 2,6 dimethylphenylene,aromatic polyether imides, polyether amide-amide, aromatic polyamidesand aromatic aliphatic polyamide combinations, polybenzimidazole,halomethylated derivatives of the above polymers on the aromatic oraliphatic groups.
 29. A fuel cell comprising a membrane according toclaim 24.